diff --git a/bin/hexagram-app.c b/bin/hexagram-app.c
index 3cb303a..cca0394 100644
--- a/bin/hexagram-app.c
+++ b/bin/hexagram-app.c
@@ -110,7 +110,7 @@ int main(int argc, char **argv) {
         return 1;
     }
 
-    if ((cluster = hexagram_cluster_new(1200, 6500, 8000)) == NULL) {
+    if ((cluster = hexagram_cluster_new()) == NULL) {
         perror("hexagram_cluster_new()");
 
         return 1;
diff --git a/include/hexagram/cluster.h b/include/hexagram/cluster.h
index 1ec4a85..50ffa2b 100644
--- a/include/hexagram/cluster.h
+++ b/include/hexagram/cluster.h
@@ -36,16 +36,11 @@ typedef struct _hexagram_cluster {
     hexagram_gauge *gauges[HEXAGRAM_CLUSTER_GAUGE_COUNT];
 } hexagram_cluster;
 
-int hexagram_cluster_init(hexagram_cluster *cluster,
-                          double rpm_min,
-                          double rpm_redline,
-                          double rpm_max);
+int hexagram_cluster_init(hexagram_cluster *cluster);
 
 void hexagram_cluster_cleanup(hexagram_cluster *cluster);
 
-hexagram_cluster *hexagram_cluster_new(double rpm_min,
-                                       double rpm_redline,
-                                       double rpm_max);
+hexagram_cluster *hexagram_cluster_new(void);
 
 void hexagram_cluster_destroy(hexagram_cluster *cluster);
 
diff --git a/src/cluster.c b/src/cluster.c
index 1d85170..7195d24 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -6,6 +6,11 @@
 #define CLUSTER_WIDTH  1280
 #define CLUSTER_HEIGHT  480
 
+#define RPM_SHIFT_MIN 2000
+#define RPM_SHIFT_MAX 6500
+#define RPM_REDLINE   6500
+#define RPM_MAX       8000
+
 #define SHIFT_INDICATOR_X 392
 #define SHIFT_INDICATOR_Y  24
 
@@ -80,10 +85,7 @@ int hexagram_cluster_filter_can_if(hexagram_can_if *can_if) {
                       sizeof(filters));
 }
 
-int hexagram_cluster_init(hexagram_cluster *cluster,
-                          double rpm_min,
-                          double rpm_redline,
-                          double rpm_max) {
+int hexagram_cluster_init(hexagram_cluster *cluster) {
     cluster->width  = CLUSTER_WIDTH;
     cluster->height = CLUSTER_HEIGHT;
 
@@ -116,8 +118,8 @@ int hexagram_cluster_init(hexagram_cluster *cluster,
                             CLUSTER_WIDTH - CLUSTER_HEIGHT / 2,
                             CLUSTER_HEIGHT / 2,
                             CLUSTER_HEIGHT / 2,
-                            rpm_redline,
-                            rpm_max) < 0) {
+                            RPM_REDLINE,
+                            RPM_MAX) < 0) {
         goto error_tacho_init;
     }
 
@@ -155,8 +157,8 @@ int hexagram_cluster_init(hexagram_cluster *cluster,
     if (hexagram_tacho_shift_indicator_init(&cluster->shift_indicator,
                                             SHIFT_INDICATOR_X,
                                             SHIFT_INDICATOR_Y,
-                                            rpm_min,
-                                            rpm_redline) < 0) {
+                                            RPM_SHIFT_MIN,
+                                            RPM_SHIFT_MAX) < 0) {
         goto error_tacho_shift_indicator_init;
     }
 
@@ -203,16 +205,14 @@ void hexagram_cluster_cleanup(hexagram_cluster *cluster) {
     hexagram_pattern_cleanup(&cluster->pattern);
 }
 
-hexagram_cluster *hexagram_cluster_new(double rpm_min,
-                                       double rpm_redline,
-                                       double rpm_max) {
+hexagram_cluster *hexagram_cluster_new(void) {
     hexagram_cluster *cluster;
 
     if ((cluster = malloc(sizeof(*cluster))) == NULL) {
         goto error_malloc_cluster;
     }
 
-    hexagram_cluster_init(cluster, rpm_min, rpm_redline, rpm_max);
+    hexagram_cluster_init(cluster);
 
     return cluster;